Defamation of Character by useless staff

I went into the Telkom store in Brooklyn Mall with a friend who had been waiting for the store to receive stock of a cellphone for more then 2 weeks. The sales assistant who helped us named Mpho had absolutely no idea what he was doing, turned his back while I was talking to him to answer his phone without excusing himself and then called my friend A **** to his face when he was reported to the store manager. The staff in that store have no idea what they are doing as each person has a different story for everything and then accuse YOU AS THE CUSTOMER of lying when they have messed up. This is not the end of this complaint!!! This will be taken further on a personal and legal level if Telkom does not sort this out